THE CANADIAN INTEGRATED MULTI-TROPHIC AQUACULTURE NETWORK (CIMTAN): 2010-2016 - WHAT HAVE WE LEARNED?

The expression "Integrated Multi-Trophic Aquaculture" (IMTA) was created in 2004. Its scope is extremely broad and flexible. It was never conceived as to be reduced to only the cultivation of salmon, kelps and invertebrates, in temperate waters, within existing salmon site limits. There are many variations on the IMTA theme, which can lead to the development of open-water or land-based systems, in marine or freshwater environments, and in temperate or tropical climates. It is not enough to consider multiple species, they have to be at multiple trophic levels, based on their complementary functions in the ecosystem. Integration should be understood as cultivation in proximity, not considering absolute distances but connectivity in terms of ecosystemic functionalities, which means that entire bays/regions could be the units of IMTA management. Having to deal with different nutrients (small particulate organic nutrients, large particulate organic nutrients and dissolved inorganic nutrients), different spatial and temporal recapturing strategies should be designed. The infrastructures for the different species should be placed accordingly, and that will certainly trigger changes in regulations, as they were designed without IMTA in mind in most countries. Dialogue with regulators and industry will be key to addressing regulatory hurdles and establishing enabling regulations for developing innovative practices.

There is a renewed interest in the mariculture of seaweeds for their integrated cultivation, the ecosystem services they provide (nutrient biomitigation, oxygen provision, carbon sequestration, reduction of ocean acidification, etc.) and novel uses. The value of the ecosystem services provided by the extractive components of IMTA systems should be recognized, accounted for and used as financial incentive tools (nutrient trading credits, for example). The IMTA multi-crop diversification approach could be an economic risk mitigation and management option to address pending climate change impacts. Perceptions should change: nutrients are not necessarily wastes and recycling, encouraged on land and in agriculture, should also be at sea and in aquaculture. Business models should embrace the emerging Integrated Sequential BioRefineries (ISBR) concept to manufacture diverse products for a wide variety of applications.

After having demonstrated the biological and environmental validity of the IMTA concept, we need to demonstrate its economic and societal validity. Initial studies indicate that economic benefits and the intangible societal benefits of IMTA are far from negligible; they, however, need to be recognized and valued properly. To give IMTA its full value, extractive species will have to be valued for more than just their biomass and food trading values, but also for the services they render and the increase in consumer trust and societal and political license to operate they provide. We need to realize that we are still in the infancy of IMTA, which will not be implemented overnight, especially in the western world. However, humans will soon not be able to continue thinking of mostly land-based agronomic solutions for securing their food, nor for providing many other derived products, but will have to turn increasingly to responsible aquanomy to manage their aquatic fields. It is time for the greener Turquoise Revolution!